Apparatus for impregnating articles



Nov. 3, 1959 E. L. DROM ETAL APPARATUS FOR IMPREGNATING ARTICLES Filed Jan. 13, 1955 m/zwmrs E. 1.. DROM R- 'J. Willi/[EACH ATTOIMQ APPARATUS FUR lh ERE GNATIN G ARTICLES Edwin L. Dram, llrookfieltl, and Robert J. Reinebach,

Westchester, Ill, assignors to Western Electric Company, lncorporatetl, New York, N.Y., a corporation of New York Application January 13, 1955, Serial No. 481,563 3 Claims. (Cl. 118- 50) This invention relates to impregnating apparatus and more particularly to apparatus for impregnating articles. such as electrical components with various types of impregnants.

An object of the invention is to provide a universal apparatus for simultaneously or individually impregnating batches of different articles with different impregnants without contaminating the impregnants.

An apparatus illustrating certain features of the invention may include a vacuum oven having a door movable to closed position to form an air tight chamber in which is mounted means for heating the chamber, a plurality of closed tanks for holding supplies of different impregnants, and a plurality of removable open containers for holding individual batches of various articles to be differently impregated. Conduits from said closed tanks inside the oven are readily insertable into said open containers for conducting the impregnant from the closed tanks to the open containers and for returning the impregnant from the open container to the closed tank, and conduits from the closed tanks connect to individual externally located supplies of the impregnants. Separate batches of electrical components may be stacked on racks in the removable containers and one or both of the containers moved into the oven and connected by the movable conduit with the closed tank containing the desired impregnant, after which the door is closed and the oven chamber heated to a temperature of approximately 260 F. to thoroughly dry the articles. The oven is then connected to a vacuum line for a predetermined length of time to exhaust all of the moisture and gases therefrom, after which control valves in the external conduits to the closed tanks are opened to efiect the flow of impregnants from the closed-tanks into the associated open containers to fill them to a predetermined level to cover the articles there in, at which time the control valves are closed, the vacuum is released, and air pressure is applied to the chamber to force the impregnants into the articles. After the articles have been impregnated the control valves are again opened and the air pressure in the oven forces the impregnants from the open containers into the closed tanks after which the valves are closed and the open containers with the impregnated articles therein are removed from the oven.

Other objects and advantages of the invention will become apparent by reference to the following detailed description and the accompanying drawings, illustrating a preferred embodiment thereof, in which Fig. 1 is a vertical sectional elevational view through the apparatus; and

Fig. 2 is a plain sectional view of the apparatus taken along line 2-2 of Pig. 1.

The present apparatus is designed to impregnate different batches of various types of electrical components such as capacitors, networks, etc, with diiferent kinds of liquid impregnants, such as liquid wax and various oils, and to accomplish the impregnation of a plurality of the the batches of components simultaneously or sequentially without contaminating the various impregnants.

The apparatus comprises a vacuum oven 15 having flat side walls, top and bottom, and a movable door 16 which is adapted to be locked in position by clamps 17 to form an air tight chamber and which is movable to open position to permit access to said even. The oven is heated by the circulation of steam through passageways in a hollow platform 22 on the bottom of the oven and through vertical hollow walls or headers 23, 24, and 25 extending upwardly from the platform 22 in spaced relation to each other.

A plurality of closed tanks 26, 27 are disposed in the chamber on the platform 22 and between the heated walls 23 and 24. Pipes or conduits 28 connect the closed tanks 26 and 27 to a pair of external auxiliary supply tanks 30 and 31. The conduits 28 extend downwardly through the tanks 26, 27, 30, and 31 to a point adjacent the bottom thereof and valves 32 are provided in the conduits for establishing and shutting off communication between the closed tanks and the auxiliary supply tanks. Conduits 35 connected to the top of each of the closed tanks 26 and 27 have movableor flexible end portions 36 for directing the impregnants from the closed tanks into a pair of removable open impregnating containers 38 and 39 which are disposed in the oven in the space between the heated walls 24 and 25. The open containers 38 and 39 are adapted to hold batches of the electrical components 10 and are supported on a roller conveyor 49 which is removably supported on the platform 22 and comprises a plurality of rollers 41 rotatably journaled in a pair of channel frames 42.

The atmosphere from the oven chamber is adapted to be evacuated therefrom by a vacuum pump 52 connected to the oven through pipes 53 and 54- and controlled by a multiposition valve 55. Air under pressure is supplied to the oven from a source of compressed air 57 connected to the oven by pipes 53 and 58 and controlled by the valve 55.

When it is desired to simultaneously impregnate two batches of electrical components with different types of impregnants, the electrical components are placed in the open containers 38 and 39 while the containers are outside of the oven and after the components have been placed therein the containers 38 and 39 are carried to the oven and moved therein. The movable end 36 of the conduits 34 are then placed in the proper containers after which the door of the oven is closed and tightly sealed. The heat is then turned on to heat the oven, the tanks 26 and 27 of impregnants, and the electrical components 10 in the containers 38 and 39 to a temperature of approximately 260 F. for about four hours to dry the components. The valve 55 is manipulated to connect the vacuum pump to the oven to evacuate the atmosphere therefrom to aid in drying the electrical components.

After the components 10 have been thoroughly dried the valves 32 in the external conduits 28 are opened to allow the atmospheric pressure to force the impregnants in the tanks 30 and 31 through the conduits 28 into the bottom of the closed tanks 26 and 27 and force the heated impregnants therein through the conduits 35 into the open containers 38 and 39' to a level suflicient to cover the electrical components 10 therein. The operator looks through a window (it) in the door of the oven to observe the level of the impregnant in the open tanks 38 and 39 and actuates the valves 32 when the level of the impregnants has risen in the open tanks to a suitable height. The vacuum is then disconnected from the oven and compressed air is supplied thereto to force the impregnants in the containers 38 and 39 into the electrical components 10 to thoroughly impregnate them.

After a predetermined length of time, during which the electrical components are thoroughly impregnated, the valves 32 are opened and the air pressure in the oven forces the impregnants in the open containers 3% and 39 through the conduits 35 into the upper end of the closed tanks 26 and 27 and forces the impregnants in the lower portion thereof through the conduits 28 into the external supply tanks 30 and 31. After the unused portion of the impregnants have been returned from the open containers 38 and 39 to the closed tanks 26 and 27, the air pressure is shut oif and the door 16 of the oven is opened and the open containers 38 and 39 with the impregnated electrical components therein are removed therefrom and the impregnated components It? unloaded from the containers.

It will be understood that batches of electrical components may be impregnated individually in one of the open containers 38, 39.

With the open impregnating containers 38 and 39 removed from the oven, the oven may be used as an impregnating tank for impregnating larger batches of electrical components with a ditferent type of impregnant. When the oven is used in this manner the roller conveyor 40 is removed therefrom and the movable ends 36 of the conduits 35 are supported in elevated positions on hooks 44 secured to the upper wall of the oven. The components are supported on suitable racks which are placed in the oven on the platform 22 between the vertical Walls 24 and 25. An impregnant from an external supply tank 45 is supplied to the oven through a conduit 46 which connects the bottom of the tank 45 with the bottom of the oven and has a valve 47 for establishing and shutting oif communication therebetween. The supply tank 45 is heated by any suitable means such as a steam jacket 48 enclosing the tank. When it is desired to impregnate a large batch of electrical components with the impregnant contained in the tank 45, the door 16 of the oven is opened and components supported on racks are placed in the oven, after which the door is closed and securely clamped. The oven is heated and the atmosphere evacuated therefrom, as explained before, to thoroughly vacuum dry the components. The valve 47 is then opened and air pressure in the tank 45 will force the impregnant therein into the oven and when the impregnant has covered all of the components the valve 4 7 is closed. The vacuum is then disconnected from the oven and air pressure applied thereto, which forces the liquid impregnant into the electrical components and after a predetermined length of time the valve 47 is opened and the air pressure forces the impregnant from the oven chamber through the conduit 46 into the supply tank 45, after which the valve 4-7 is closed and the impregnated components removed from the oven.

Thus, with the above-described apparatus a plurality of batches of different electrical components may be impregnated with different impregnants simultaneously or individually and without contaminating the impregnants one with another. I

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of this invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles or" the invention and fall within the spirit and scope thereof.

What is claimed is:

1. An apparatus for impregnating articles with various types of impregnants comprising an oven having a movable closure to form an air tight chamber, a plurality of closed tanks in said chamber for holding supplies of different impregnants, conduit means from said closed tanks to external supplies of said impregnants, a plurality of open containers removably supported in said chamber for holding articles to be impregnated and for receiving and holding impregnants from the closed tanks,

means for heating said chamber to dry said articles and to simultaneously heat the impregnants in said closed tanks, means for evacuating the atmosphere from the chamber, means for eifecting flow of the impregnants between said closed tanks and said open containers whereby said impregnants may be transferred from the closed tanks into said containers to cover the articles, and means for supplying compressed air to said chamber to force the impregnants into the articles.

2. An apparatus for impregnating electrical components with various types of impregnants comprising an oven having a door movable to a closed position to form an air tight chamber, a plurality of open containers removably disposed in said oven for holding individual batches of articles to be impregnated, and for receiving and holding impregnants for the articles, a plurality of closed tanks in the oven for holding supplies of diiierent impregnants, conduit means from said closed tanks to external supplies of said impregnants, conduit means from said closed tanks insertable in said open containers for conducting the impregnants between said closed tanks and said open containers without contaminating the different impregnants and the inside of the oven while using the different impregnants, means for heating the oven to dry the articles and to heat the impregnants therein, means for evacuating the atmosphere from the oven, valve means in said first mentioned conduit means for controlling the flow of the impregnants between said closed tanks and said open containers whereby the impregnants may be flowed from said tanks into said containers to cover the electrical components therein, means in said oven for permitting the observation of the level of the impregnants in said containers, and means for supplying compressed air to said oven to force the impregnants into said electrical components and in cooperation with said valve means to force the flow of impregnants from said open containers into said closed tanks after the components have been impregnated.

3. An apparatus for impregnating electrical components With various types of impregnants comprising an oven having a door movable to closed position to form an air tight chamber, means for connecting said oven to a source of vacuum, means for connecting said oven to a source of compressed air, means for heating the oven, a plurality of closed tanks in said oven for holding supplies of different impregnants, conduit means from said closed tanks to external supplies of said impregnants, a plurality of open containers removably supported in said chamber for holding individual batches of electrical components to be impregnated, and for receiving and holding impregnants from the closed tanks, means for eiiecting the flow of the impregnants between said closed tanks and said open containers, a receptacle outside of said oven for holding a supply of another impregnant, means for heating said receptacle, and means for effecting the flow of said other impregnant between said receptacle and said oven.

4. An apparatus for impregnating articles comprising an oven having a door movable to closed position to form a hermetically sealed chamber for holding articles to be impregnated, a receptacle disposed externally of the oven for holding a supply of one impregnant, conduit means interconnecting said oven and said receptacle for conducting said impregnant therebetween, valve means in said conduit means for establishing and shutting 01f communication between said oven and said receptacle, means for heating said oven, means for heating said receptacle, means for evacuating the atmosphere from said oven, means for supplying compressed air to said oven, a closed tank in said oven for holding a supply of a diiierentimpregnant, an open container removably supported in said oven for holding articles to be impregnated and for receiving and holding impregnant from the closed tank, conduit means connected to said closed tank and insertable in the open container for establishing communication between the closed tank and said open container for the flow of the impregnant therebetween, a supply tank disposed externally of said oven for holding a supply of said difi'erent impregnant, conduit means interconnecting said closed tank and said supply tank, and valve means in said last mentioned conduit means for efiecting the flow of the irnpregnant between said closed tank and said open receptacle.

5. An apparatus for impregnating articles with various types of impregnants comprising an oven having a door movable to a closed position to form an air tight chamber, a plurality of closed tanks in said oven for holding supplies of different impregnants, a plurality of open tanks removably supported in said oven for holding individual batches of articles to be impregnated, means for heating said oven, means for evacuating the atmosphere from said oven, means for supplying air under pressure to said oven, conduit means connected to the upper portion of said closed tanks and insertable into said open tanks for selectively establishing communication between said closed and said open tanks for conducting the impregnants therebetween, a plurality of external supply tanks for holding supplies of said impregnants, conduit means connecting said external supply tanks individually with the bottom of said closed tanks for conducting the impregnants therebetween, and valve means in said last named conduit means for controlling the flow of said impregnants from one tank to another.

6. An apparatus for impregnating articles comprising an oven having a door movable to closed position to form an air tight chamber for supporting a batch of articles to be impregnated, a receptacle disposed externally of the oven for holding a supply of one impregnant, a conduit interconnecting said oven and said receptacle for conducting said impregnant therebetween, a valve in said conduit for establishing and shutting 01f communication between said oven and said receptacle, means for heating said oven, means for heating said receptacle, means for evacuating the atmosphere from said oven, means for supplying compressed air to said oven, a plu rality of closed tanks in said oven for holding supplies of different impregnants, a plurality of open containers removably supported in said oven for holding batches of articles to be impregnated, conduit means for estab lishing communication between the closed tanks and said open containers for the flow of impregnants therebetween,

a plurality of supply tanks disposed externally of said oven, conduit means interconnecting said closed tanks and said external supply tanks, and valve means in said last named conduit means for effecting the flow of im pregnants between said closed tanks and said open containers.

7. An apparatus for impregnating articles with various types of impregnants comprising an oven having a door movable to a closed position to form a sealed chamber, a plurality of open containers removably disposed in said chamber for holding individual batches of articles to be impregnated and different impregnants for the articles, a plurality of tanks for holding supplies of different impregnants, means for heating the chamber, means for evacuating the atmosphere from the chamber, means for selectively transferring the impregnants from the tanks to the open containers to cover the articles therein while the open containers are in the sealed chamber, and means for supplying compressed air to said chamber.

8. An apparatus for impregnating articles with various types of impregnants comprising an oven having a movable closure to form an air-tight chamber, a plurality of closed tanks in said chamber for holding supplies of different impregnants, a plurality of open containers removably supported in said chamber for holding articles to be impregnated and for receiving and holding impregnants from the closed tanks, means for heating said chamber to dry said articles and to heat the impregnants in said closed tanks, means for evacuating the atmosphere from the chamber, means for supplying compressed air to said chamber, and selectively operable means for effecting the flow of the impregnants between said containers and said closed tanks.

References Cited in the file of this patent UNITED STATES PATENTS 577,671 Telsa Feb. 23, 1897 1,315,763 Dickey Sept. 9, 1919 1,594,124 Shrader July 27, 1926 1,604,230 Latimer Oct. 26, 1926 1,818,976 Goff Sept. 22, 1930 2,009,232 Hood July 23, 1935 2,120,816 Schroll June 14, 1938 2,207,186 Wolfi July 9, 1940 

